The search for culture-free or culture-fair tests has proved endless, because “culture” can be used so broadly as to encompass virtually anything a human does. People live in society, and societies transmit the habits of previous generations. There was a time in the debates after Jensen’s 1969 paper when psychologists believed that they could estimate the cultural loading of a test by inspecting the items. Indeed, my very first published paper attacked Jensen for arguing that the Wechsler subtest of Block Design was relatively culture-free, such that black-white differences on that test were probably genetic, whereas I felt it depended on access to constructional toys.
How does one determine the cultural loading of an intelligence test item? A Dutch team have plunged into these waters (strictly speaking they are below sea level, but no matter) and have rated subtests thus: Cultural load was operationalized as the average proportion of items that were adjusted in each subtest of the WAIS-III when the scale was adapted for use in 13 countries (Georgas et al., 2003). To my eye that is certainly a language adjustment, though I wonder whether it allows for the different availabilities of artefacts in the home (not that I can think of an easy way to measure that).
Kees-Jan Kan, Jelte M. Wicherts, Conor V. Dolan, and Han L. J. van der Maas. On the Nature and Nurture of Intelligence and Specific Cognitive Abilities: The More Heritable, the More Culture Dependent. Psychological Science 24(12) 2420–2428
On this measure, Vocabulary is the most culture dependent subtest. On first glance that makes sense: the easiest way to learn a language is to be immersed in the particular culture that speaks it. However, that merely covers translating words from one language to another. Even within a culture, even the most ethno-centric citizens do not learn all the available words: intelligence is required for that.
From an early post on Vocabulary: Some people have the simplistic notion that vocabulary must be determined by mere exposure to spoken language. That is necessary, but far from sufficient, as even children work out. They notice patterns, informal rules, and the contexts in which communication takes place. “The acquisition of meaning is based on the eduction of meaning from the contexts in which the words are encountered”. (So, even if the word “eduction” in the quotation from page 146 of Jensen’s “Bias in mental Testing” is unfamiliar, you will not be surprised to deduce that it means “To assume or work out from given facts; deduce”).The meaning of a word is acquired in some contexts which permits at least some partial inference as to its meaning. By hearing or reading the word in different contexts, through a process of generalization, discrimination and eduction one can guess at the essence of the meaning of the word, so as to use it (experimentally) oneself the next time a similar context presents itself. Words move from being unfamiliar to familiar, from familiar but not really understood to being familiar and partly understood (at which stage the explanations given about the meaning of the word are threadbare and inaccurate), and from there to being explained by use of synonyms (though those can range from partial to full understanding as shown by the power of the explanations and definitions).
The Methods section is explicit about how things were calculated, one step at a time: a model approach to be commended.
The culturally loaded tests have higher heritabilities.
The authors conclude:
Each subtest’s proportion of variance in IQ shared with general intelligence was a function of cultural load: The more culture loaded, the higher this proportion. In addition, in adult samples, culture-loaded tests tended to have greater heritability coefficients than did culture-reduced tests, and there was a relationship between subtest’s proportion of variance shared with general intelligence and heritability. In child samples, these relationships were in the same direction, but correlations were small and insignificant.
They sound a cautionary note about the data, but their substantive point is:
A correlation between, for instance, g loading and heritability coefficient is in line with the hypothesis that the g factor is the most heritable factor (Jensen, 1998), but a test of the significance of this correlation does not provide the means to test whether the g factor is indeed the most heritable factor1 (Dolan & Hamaker, 2001). The method merely serves to evaluate competing theories of intelligence (Rushton & Jensen, 2009): A significant correlation denotes that a phenomenon exists that is in need of theoretical explanation. Theories that account for the correlation are stronger (with respect to this correlation) than are theories that do not account for it or are silent about it. The same line of reasoning holds for the correlations of cultural load with g loadings and heritability coefficients.
Having given their conclusions, the team then go against normal sequence and start a discussion.
Our result showing that culture-loaded knowledge tests (crystallized tests) are more strongly related to general intelligence than are culture-reduced cognitive processing tests (fluid tests) fits better with the idea that g loadings reflect societal demands (Dickens, 2008) than that they reflect cognitive demands (Jensen, 1987). Furthermore, in adult samples, our finding that the heritability coefficients of culture-loaded tests tend to be larger than those of culture-reduced tests calls for an explanation, given that this result does not follow from the subtest-complexity and investment hypotheses of g theory and fluid-crystallized theory.
After discussing some options they plump for genotype-environment covariance.
Because the acquisition of knowledge depends on cognitive processing, individuals who develop relatively high levels of cognitive-processing abilities tend to achieve relatively high levels of knowledge. High achievers are more likely to end up in cognitively demanding environments that encourage and facilitate the further development of a wide range of knowledge and skills. The contents and organization of these environments largely reflect societal demands. These societal demands thus influence the degree of dynamical interaction among cognitive processes and knowledge and, hence, their intercorrelations. In this way, the societal demands determine IQ-subtest loadings on the general factor of intelligence and, eventually, the degree to which broad-sense heritability coefficients of IQ subtests include the effects of (growing) genotype-environment covariance. In view of theoretical parsimony, we conclude that the assumption of a true causal g can be incorporated but that this is not required.
This paper presents interesting, counter-intuitive findings, which deserve replication on other samples and other psychometric tests. As to their favoured genotype-environment effect, I don’t see how bright people can obtain high levels of knowledge without being bright in the first place. They don’t develop intelligence, they have that ability in varying degree and use it to develop their knowledge to varying degrees. I am still working this out, but I think that ability is prior, and therefore more likely to be causal.
See what you think.